Experimental Spray Characterization of Biofuels in a Constant Volume

ranchocucamongabrrrAI and Robotics

Nov 6, 2013 (3 years and 11 months ago)

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Experimental Spray Characterization of Biofuels in a Constant Volume
Chamber

By

Vipul Chaudhary


The spray characteristics of the fuel highly influence the emissions from diesel engines.
Spray development plays an important role in improving the combustion and emission
characteristics of any fuel because it directly affects the air fuel mixture format
ion in the
cylinder. Spray characteristics of the fuel mainly depend on the injection pressure, fuel
density, fuel viscosity, ambient gas pressure and temperature. Among these, the effect of
ambient gas pressure is a very important parameter having a direc
t effect on spray
pattern.

This thesis investigates the effect of ambient gas pressure on the spray characteristics like
spray tip penetration, cone angle and spray area in a specially designed and fabricated
constant volume spray chamber by employing spr
ay visualization technique and image
processing method. The constant volume chamber has been designed to be able to
withstand an ambient pressure up to 10 bars. The image analyzed was chosen from one
full injection event images, grabbed by a set of spray v
isualization instruments consisting
of a high speed camera, white light source, and image acquisition and analysis software.
The fuels used for the investigation were Karanja straight vegetable oil (K100)/ blends
(K5, K20), Karanja biodiesel (KB100)/ blend
s (KB5, KB20), Jatropha straight vegetable
oil (J100)/ blends (J5, J20), Jatropha biodiesel (JB100)/ blends (JB5, JB20) and mineral
diesel.

The results of macro analysis showed that as the ambient pressure increases from 1 bar to
9 bars, the spray tip pen
etration decreases, cone angle increases and also spray area
increases. Comparing results of Karanja biodiesel/blends and Jatropha biodiesel/blends
with diesel, KB100 and JB100 had highest spray tip penetration, cone angle and spray
area followed by KB20,
KB5, diesel and JB20, JB5, diesel respectively, because of fuel
density difference. Compared to the Karanja straight vegetable oil/blends and Jatropha
straight vegetable oil/blends with diesel, K100 and J100 have highest spray tip
penetration, cone angle a
nd the spray area followed by K20, K5, diesel and J20, J5, diesel
respectively, because of the same reason. Further the intensity level of light on the spray
was analyzed and studied for all fuels. The investigations reveal that the atomization level
accor
ding to the intensity level was superior in biodiesel blends as compared to straight
vegetable oil blends at same injection and ambient pressure condition and at same axial
distance from injector orifice.